Mill feeder for large material



April 17, 1962 G. D. BECKER ETAL MILL FEEDER FOR LARGE MATERIAL Filed Jan. 13, 1958 3 Sheets-Sheet l m z s 0 we w f N m a w M? M7 M3 7 X A 6 Q .1 Fl; W W u 6 N\ f M M Q m N 3 Q R ,p Q 0 mm NM \M VQ QNRM %m. \m Q 0 0 mm mm April 17, 1962 G. D. BECKER ETAL 3,030,034

MILL FEEDER FOR LARGE MATERIAL 3 Sheets-Sheet 2 Filed Jan. 13, 1958 INVENTOR5. DAV/ 4. CATV i775} BY iflfi 0. EKG/(5?,

April 17, 1962 G. D. BECKER ETAI.

MILL FEEDER FOR LARGE MATERIAL 's Sheets-Sheet 3 Filed Jan. 15, 1958 Y INVENTOR5. 1 414.0 ,4 mix 775" BY 650/?64" 0. fife/(69,

United States EfiEfifiBi Patented Apr. 17, l9tl2 fine 3,030,034 MILL FEEDER FOR LARGE MATERIAL George 1). Becker, Wauwatosa, and David A. Cheyette,

Milwaukee, Wis., assignors to Nordherg Manufacturing Company, Milwaukee, Wis., 21 corporation of Wiscousin Filed Jan. 13, 1958, Ser. No. 708,701 8 Claims. (Cl. 24l--33) Our invention relates to a new and improved method and apparatus for feeding raw material to a processing machine such as a crusher. The system and apparatus are particularly useful in feeding quarried, pit run, or mined materials such as ore or stone into gyratory or jaw type crushers.

Prior methods of feeding quarried material to large crushing machines have definite limitations. The most awkward way of feeding material to a crusher is to back a truck up to the crusher and empty the load directly into it. This method has several very serious draw-backs.

in the first place there is no way of accurately controlling the rate of feed of material from the truck to the crusher. The crushers are designed to receive a constant supply of raw material. Large surges will overflow the maw of the crusher and spill over the sides before enough material has been passed through to make room for the jammed up material on top. In addition this method is extremely expensive for it ties up the truck driver and the truck for a length of time sufficient to completely empty the body of the truck, thus running up the cost of operations considerably. The backing and maneuvering of the truck wears the equipment and there is greater chance for misalignment and accidents.

A second type of feeder that has been used heretofore is a machine known as a pan feeder. This machine has been unsatisfactory for use with very large crushing machines however. The cost of manufacturing these pan feeders in large sizes has been very high and the cost of maintenance during operation is also high.

Accordingly a primary object of our invention is the provision of a method of feeding material to a gyratory crusher or the like wherein the rate of feed is precisely controlled to yield an even, steady constant volume stream of raw material. v

Another object is the provision of a system of conveying raw materials from the quarry to the gyratory crusher in a quick, economical manner whereby bottlenecks due to truck tieups at the dumping point are eliminatedi Another object is the elimination of surge feeding to gyratory crushers or the like and the consequent prevention of bridging and overflowing of the machine.

Another object is the provision of a feeding and dumping system whereby turning and backing of trucks conveying the raw material from the quarry or other loading zone to the crusher area is completely eliminated.

A further object is the provision of an arrangement which is extremely economical to install and operate and requires little or no skill on the part'of the operators of the shuttle trucks.

Another object is the provision of a feeding apparatus including a controlled feeder blade mounted to smoothly and efficiently feed raw material into the rnaw of a gyratory crusher or the like.

Yet another object is the provision of a feeder blade which is adapted to divide and guide the material in material away from the supporting structure of the crusher.

Another object is the provision of an automatic or manual system for operating a feeder blade having a built-in safety circuit for suspension of operation of the feeder blade when trucks or unauthorized personnel are in the crusher feeding area.

A further object is the provision of a propulsion unit for a feeder assembly which will automatically compensate for variations in the point of application of forces on the assembly resulting from depositing batches of raw material at points substantially out of alignment with the center line of the path of travel of the feeder blade to thereby prevent skewering of the blade.

Other objects will become apparent from time to time throughout the course of the following specification.

We illustrate our invention more or less diagrammatically in the accompanying drawings wherein,

FIGURE 1 is an elevation partly diagrammatic in outline of our crusher feeding system;

FIGURE 2 is a plan view of a portion of the system shown in FIGURE 1;

FIGURE 3 is a detailed view of a portion of the feeder blade carriage;

FIGURE 4 is a view taken on the line 4-4 of FIG- URE 3; and

FIGURE 5 is a schematic drawing illustrating the operating and safety circuits.

Like reference numerals will be used to refer to like parts throughout the several views.

Referring now particularly to FIGURE 1, a raw material processing device such as a gyratory crusher or order to prevent injury to the crusher by directing. the t the like is indicated at it as having a spider l2 bridging the open maw 14 of the crusher. The crusher may be rigidly lined in the ground l6. Immediately to the left of the crusher is a bar. grizzly 18 which in this instance is inclined downwardly with respect to an upper floor 22. T he bar grizzly acts as a slide or funnel for channeling raw material into the maw of the crusher. It may have openings of any suitable size, but in general the Width of the opening between the individual grates will be such as to permit fines to pass through to a conveyor or suitable receptacle below. The grates may be set sufficiently far apart to pass material of the same size as that produced by the crusher. It will be understood that the crusher could also be at a higher level than the floor 22 in which event a conveyor could be used to carry the raw material upwardly.

At Zil we have indicated generally a feeder blade assembly which runs on a pair of rails 21 resting upon the ground 22. it will he understood that the ground 22 may in effect consist of a slab of reinforced concrete 72 or other material capable of taking severe impact loads without damage. On top of the concrete is a floor 73 formed preferably from steel which takes the direct impact of the material when it is dumped from the trucks. Old jaw plates, crusher concaves and mill liners might be used for this purpose. relatively level and extend not only between the rails 21 but to a considerable distance outside the rails so as to form a dumping area 71. The steel plate should come as close as possible to the inside edges of the rails. A slot 76 in the floor receives rails 21 and cables 43 and 44 as best seen in FIGURE 4. At we have diagrammatically indicated a truck loaded with quarried material positioned in the dumping area preparatory to discharging.

The feeder blade assembly consists essentially of .a

We prefer that the floor 'be' blade.

feeder blade 24 mounted upon a carriage 30 which is propelled by a cable, reel and motor assembly 40. The blade itself is composed of a relatively hard material and is positioned at right angles with respect to the longitudinal axis of the rails. After a truck has dumped its load, the ore or similar material will usually form a cone if it is dropped in substantially one spot. The blade should therefore be high enough to push the entire pile towards the crusher without having the top of the cone slide backwards onto the blade assembly. The blade may be inwardly flared at the ends as at 25 and 26 to help contain the material within its path. A divider bar 28 may extend outwardly from the front face of the blade at its midpoint in order to force large chunks to one side or the other of the blade in order to avoid dropping the chunks directly onto the spider arm 12 of the crusher.

The carriage and propulsion assembly 30 consists generally of a framework 31 upon which the feeder blade 24 is mounted. A protecting sheet or cover 32 may extend backwardly from the top of the blade to prevent rock and other raw material from falling onto the mechanism beneath. The carriage moves along the rails 21 on four flanged wheels 34 mounted on suitable axles 35 journaled in the carriage. While these wheels may be mounted at any convenient distance with respect to the center point of the feeder blade, we have found that by mounting them near the outer edges of the blade a greater control is achieved over the rate of feed. There is less likelihood of the blade tilting or becoming skewered with respect to the longitudinal axis of its path of movement due to a pile of material being deposited near one end of the blade.

The propulsion assembly consists of a pair of wire rope cable reels 42 each reel having a front cable 43 and a back cable 44 attached thereto. The free ends of the cables are attached to the fixed structure. Looking at FIGURE 2, for example, the right-hand end of front cable 43 is shown attached to the rail at 45 slightly beyond the extreme point of movement of the feeder The left-hand end of the cable may be attached by means of a suitable fitting such as 46 to the cable reel itself. The right-hand end of rear cable 44 may be attached to the reel by means of the same cable attachment 46 or separately, if desired. The back cable extends rearwardly to the eye bolt of a cable tensioner 47, which includes a spring and nut fitted on the eye bolt that may be adjusted to put tension in the cable. By positioning the reels near the extreme edges of the feeder blade, the blade will always remain disposed at substantially right angles to the center line of its linear path of travel despite the location of the deposited raw material. The moments resulting from the unsymmetrical position of the load are counterbalanced and wear is greatly reduced.

The cable reels are mounted on suitable bearings 4 which in turn are rigidly connected to a cross-connecting shaft 50 located approximately midway between the flanged wheels 34. As the shaft 50 rotates, the cable reels, which are of equal diameter, will pay out and simultaneously reel in equal lengths of cable.

The propulsion unit consists of a motor 52 mounted on frame 31 and a speed reducer 54 connected to the output shaft of the motor.

A mast 58 is revolvably mounted adjacent the rails and sufficiently removed from the path of the feeder blade so that the blade will clear themast. A boom 59 is pivoted at the top of the mast 58 and an electric power cable 60 carried by the boom furnishes power to the motor 52.

At 80 we have indicated a photo-electric cell which projects a light beam across the dumping area 71 to a suitable mirror 81 whichmay be attached'to the mast 58, for example.

At;90.we.have shown. a. red. and green traflic light which indicates to the truck drivers when the dumping area is clear of the moving blade, and at 100 there is diagrammatically indicated a control house where the crusher operator may in one spot control the operation of the gyratory crusher and the feeding system.

Referring now to FIGURE 5, the operating circuit and safety circuits are diagrammatically illustrated.

The motor circuit includes a source of power 62, a starter 64, and a line 66 extending from the starter to the mast 58. It will be understood that the line 66 may run from the starter upwardly and across the open dumping space to the mast. As diagrammatically illustrated in FIGURE 5, it may extend beneath the level of the floor and run up the inside of the mast and out of the boom. A control panel 65 in the operators house 100 has suitable leads 61 running to the starter.

The safety circuit consists of a red and green traflic light and a photo-electric cell.

The traffic light is automatically operated by a limit switch 92 placed at the rear of the path of travel of the feeder blade. Leads 93 and 95 connect the light to the switch and source of power 94. This simple circuit is so arranged that when the blade is in its retracted position, that is, at the left-hand end of FIGURES l, 2 and 5, the green light will show. When the blade starts forward the limit switch will trip in the opposite direction and the red traific light will show, thus warning the truck driver to keep out of the area.

The red and green stop light is merely a preliminary warning or indicating device and if a truck or unauthorized person inadvertently happened to be in the path of travel of the feeder blade, he would be in great danger of being pushed toward the crusher. Thus the photoelectric cell is designed to interrupt the motor circuit of the feeder blade so that it cannot move while a truck or some other object capable of interrupting the electriceye circuit is in the way. The photo-electric cell circuit consists of a standard photo-electric cell 80, a mirror 81 positioned in any convenient location, for example on the mast 58, a pair of leads 82 connected to the power source 94, and another pair of leads 84 connected to relay 86 which is interposed in the line between the power source 62 and the motor 52. When the light beam 83 is interrupted by a truck or some other obstruction, the circuit to the feeder blade motor is interrupted to prevent movement of the blade so long as the truck or other object is in the area.

The control house shown above the gyratory crusher is for the use of the crusher operator. Normally the operator is provided with a small weather-proof house containing starter buttons and operating indicators such as gauges indicating oil temperatures, operation of oil pump, oil pressure, main motor operation, and perhaps even bin level indicators and conveyor indicators. In order to integrate the feeder blade system with its safety circuits into this already existing system, it is only necessary to add a push-button control to the same control board in which the other indicators are mounted. This push-button control may consist of a forward and reverse button which will allow the operator to move the blade forward or backward at full speed by holding down one button, or alternately inching the feeder blade by short jabs at the button.

The circuits associated with the invention are quite simple and have been indicated diagrammatically only. The circuits do not in themselves form the invention and it will be understood that equivalent circuits could be used to perform the same tasks. Many of the parts of our circuits are standard such as the photo-electric cell. This cell comes as a complete package and requires only the placing of the mirror to reflect the light.

The practice of the method and the use of the apparatus is substantially as follows.

There has been a long felt need for an economical speedy, method of feeding raw materialto crushers, By

our method a truck can be brought up to a crusher with a minimum amount of eifort, quickly drop its load and proceed back to the quarry to receive another load, and the feed to the crusher will be uniformly maintained between successive trips of the truck. This reduces considerably the number of trucks required to service a crusher with corresponding savings in equipment, rental and labor costs.

Before commencement of operations the front cables 43 on each side of the carriage are securely fastened to the stationary structure at 45, laid in the slots 76, wound around the cable reels, preferably. an equal number of turns, and securely fastened thereto by a clamp 46. The rear cables 44 are then fastened to the cable reels in any suitable manner and extended backward to the cable tensioners. Alternatively, if a single cable on each side is used, the cable is securely fastened to the stationary structure, laid in the slot 76, wound around the cable reel and extended backwards to the cable tensioners.

By tightening the nut on the cable tensioner, the tension in the cable may be so adjusted that there will be little or no slack, and accordingly the carriage will be instantly responsive to the operation of the motor when the crusher operator energizes the motor circuit in the control house. This instantaneous operation is important, for when the material is being inched over the bar grizzly it is important to avoid large surges of material which will fill up and overflow the maw of the crusher. By maintaining a fine control over the movement of the blade, a steady supply can be maintained.

Starting at the beginning of the days operation the first truck from the quarry will drive up into the dumping area 71 and drop its load at once. It is not necessary that the driver discharge the load carefully and in a controlled manner. The only requirement is that he position thetruck so that the bulk of the material will fall within the path of the feeder blade. The truck may be driven up to the dumping station in One direction, the load dropped and the truck continue on through the station in the same direction, thus avoiding the necessity of any awkward backing and turning in order to position the truck.

Upon approaching the dumping area the operator watches the signal lights, If the red and green stop light shows red, he will stop and wait until the green signal is on. This will then indicate that the feeder blade is in its retracted position. When the operator sees the green light, he drives his truck into the dumping area. The truck body will'interrupt the beam 83 projected by the photo-electric cell 80 and by operationof relay 86 the motor circuit will be cut out so that there is no possibility of the feeder blade moving forward toward the bar grizzly and crusher while the truck is in the feeding area.

After the truck has dumped its load and moved out of the path of beam 83, the motor circuit is re-established. The operator in the operators house 100 then pushes the forward button on his control board to operate the carriage motor 52. As the feeder blade 24 begins to move forward, the limit switch 92 is tripped in the opposite direction and the red light flashes on thus warning the next truck driver to stay out of the dumping area. The operator then gauges the travel of the feeder blade and controls it by use of the forward button. If the load has been dumped relatively close to the bar grizzly, he may want to advance the feeder blade at a relatively rapid rate until the blade makes contact with the dumped pile maw of the crusher in order to prevent material falling down alongside the crusher.

As the carriage moves forward the rotatable mast 58 will swing counter-clockwise from its position shown in FIGURE 2 to permit the electric power cable to follow the travel of the feeder blade.

During the forward movement of the feeder blade the material will tend to spread out laterally towards the edges of the blade. That is, instead of moving as a unitary mass from the spot in which it was dumped, the further the material travels the more extended it will become. The inwardly flared edges 25 and 26 then function to confine the material.

As the carriage moves forward the divider bar 28 will hit the larger rocks and force them towards the edges of the blade so that when they are eventually pushed over the bar grizzly they will not fall directly upon the spider arm 12 of the gyratory crusher. It will be understood that many variations may be made in the size, shape and disposition of parts. Accordingly, it is intended that the foregoing description be taken as illustrative only for we do not intend to be limited except by the scope of the following appended claims.

We claim:

1. A system for feeding raw material to a continuously operated crusher including a substantially level surface disposed adjacent the crusher, a feeding assembly including a supporting structure mounted for travel across the surface up to a conveying and guiding means, a feeder plate carried by the supporting structure and adapted to engage and force a batch of raw material deposited on the surface between the feeding assembly and the crusher in approximately a linear path toward the crusher, the feeder plate including guiding means consisting of at leastv one projection on the plate for channeling the raw material into given paths of movement, a motive power system connected to the feeding assembly for propelling it across the surface, control means for regulating the speed of travel of the feeding assembly with respect to the capacity of the crusher in order to correlate the movement of the raw material into the crusher with the rate of consumption of the crusher, and a safety system integrated in the motive power system capable of arresting the movement of the feeding assembly and attached feeder plate in response to the position of an object on the level surface in the path of travel of the feeder plate.

2. The system of claim 1 further characterized in that the motive power system includes aligning means for the feeder assembly adapted to impart a uniform controlled movement to the feeder blade and to a batch of material whose center of gravity does not lie directly in front of the center of the feeder blade.

3. The system of claim 2 in which the aligning means is adapted to maintain the feeder blade at right angles to the linear path traversed by the feeder blade in urging the material toward the crusher.

4. The system of claim 3 further characterized in that the motive power system includes at least a pair of tension transmitting members connected to the feeder assembly and a stationary base, said members being spaced a substantial distance apart and adapted for uniform extension and retraction to accommodate forward and reverse movement of the feeder assembly to thereby compensate for unequal pressure distribution along the face of the blade toprevent skewering of the blade.

5. The system of claim 4 in which the tension transmitting members are connected to the feeder assembly at points near the edges of the feeder bladeso that the points of application of force to the blade will generally straddle the center of gravity of the deposited batch of raw material.

'6. The system of claim 1 further characterized in that the conveying and guiding means is interposed between the substantially level surface and the crusher to thereby 71 convey and direct raw material from the surface to the crusher.

7. A control system for a material processing machine feeding system having a material receiving area disposed adjacent a processing machine and a feeding assembly for urging raw material deposited upon the area into the machine, the feeding assembly including a source of motive power adapted to impart translatory motion to the assembly along a predetermined path traversing the material receiving area, said control system including: a source of electric power, means for transforming electric power into a beam of light, said beam being directed across the raw material receiving area, a connection between the motive power system and the source-of electric power, and power interrupting means in the connec-- 1 tion responsive to interruption of the beamand operable to cut off electric power to the source of motive power.

8. The control system of claim 7 further including means for indicating the position of the feeding assembly in the material receiving area, and limit means operable inresponse to movement of the feeding assembly to a predeterminedposition' in the material receiving area for actuating the indicating means.

References Cited in the file of this patent UNITED STATES PATENTS 369,117 Marchant Aug. 30, 1887 984,249 Weschler Feb. 14, 1911 1,525,450 Kneebone Feb. 10, 1925 1,609,299 Kennedy Dec. 7, 1926 1,922,972 Miller Aug. 15, 1933 2,381,351 Hardinge Aug. 7, 1945 2,456,074 Newhouse Dec. 14, 1948 2,495,096 Grimaldi Ian. 17, 1950 2,737,289 Peters Mar. 6, 1956 OTHER REFERENCES Metal Mining Practice, Bulletin 419, Bureau of Mines, published 1939, pages 370-374. 

